Over the road tank trucks and trailers for transporting bulk materials such as dry and liquid chemicals, petroleum, milk, and like products, frequently utilize large diameter semi-rigid filling and discharge hoses which are coupled between appropriate fittings on the tank and remote fittings at the supply or discharge terminals. Such hoses are usually made up of elongated sections having a length in the order of 20 feet.
When not in use for filling or discharging the tank containers the hose lengths are usually stored in elongated cylindrical housings or "hose tubes" carried adjacent the tank and having the open ends thereof fitted with some type of closure means so that the hose sections are readily accessible when needed, but otherwise are secured against loss or theft when not in use.
Presently known closure means for this purpose comprise annular frames fitted over and secured to the ends of the cylindrical storage tubes and a cap or closure door pivotally joined to the frame for cooperation with the latter in enclosing the storage tube ends. The frame and cap or door are usually provided with peripheral extensions for permitting the use of a padlock to lock the door in closed position. One such known door assembly employs an elongated cantilever spring means which is attached to the door frame in a manner permitting the spring means to pivot across the door against a wedge for maintaining the door closed under spring pressure. This closure system is relatively cumbersome and inconvenient to use and operate and is susceptible to breakage and damage of the spring particularly by interferance with washing equipment, such as power brushes and the like. In addition since the spring must be pivoted to a non-interfering position in order to release the door, it is inconvenient to use on adjacent storage tubes. Thus there is a need for an improved, simplified, positive acting security system for hose tube doors and the like to which the present invention is directed, although its teachings and concepts are applicable to other types of closure environments.